HR: 0800h
AN: V11A-0369    [Abstracts]
TI: Scaling Relationships for Deep and Shallow Magma-Driven Intrusions
AU: * Bunger, A P
EM: andrew.bunger@csiro.au
AF: CSIRO Petroleum, Private Bag 10, Clayton South, Vic 3169, Australia
AU: Detournay, E
EM: detou001@umn.edu
AF: University of Minnesota, Department of Civil Engineering, 500 Pillsbury Drive, Minneapolis, MN 55455, United States
AB: Components of the elastic fracture/lubrication model have been used in the past to evaluate the growth of magmatic intrusions, but it has remained unclear whether this model is capable of producing results which are consistent with field data. The mathematical model used in this study accounts for full coupling between fluid flow and the elastic deformation and fracture of the rock as well as the mechanical influence of the Earth's surface on shallow intrusion growth. A scaling method is used to derive approximate relationships between thickness and length for circular intrusions growing in each of four propagation regimes that correspond to deep and shallow cases which can be either viscosity or toughness dominated. Application of these results to particular field cases requires careful consideration of specific governing parameters, geometry, and other local conditions. In contrast, this work relies on choosing governing parameters such as magma viscosity and injection rate from published ranges and then employing the derived relations to bound the model's solution domain using a Monte-Carlo technique. In this way the viability of the model is examined in broad terms in order to understand its applicability to modeling magmatic intrusions in general. The results indicate that the solution domain corresponds well with available data both in the values of the estimated thickness to length ratios and in the tendency for small/deep intrusions to favor lateral spreading while large/shallow intrusions favor vertical inflation or growth with a fixed thickness to length ratio.
DE: 3642 Intrusive structures and rocks
DE: 8020 Mechanics, theory, and modeling
DE: 8137 Hotspots, large igneous provinces, and flood basalt volcanism
DE: 8145 Physics of magma and magma bodies
DE: 8400 VOLCANOLOGY
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting